Handle js interop members in impact computation.

pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart

Index: pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart
diff --git a/pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart b/pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart
index b49c7a8ee668a6d85252cfc55f88b3ffaae9915a..b79ec5f85373b576d7c40bcecea4d1b68784281c 100644
--- a/pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart
+++ b/pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart
@@ -17,6 +17,7 @@ import '../elements/modelx.dart';
 import '../elements/resolution_types.dart';
 import '../elements/types.dart';
 import '../js_backend/js_backend.dart';
+import '../js_backend/native_data.dart';
 import '../kernel/element_map.dart';
 import '../kernel/element_map_mixins.dart';
 import '../kernel/kernel.dart';
@@ -87,6 +88,10 @@ class KernelAstAdapter extends KernelToElementMapBaseMixin
     _typeConverter = new DartTypeConverter(this);
   }
 
+  @override
+  NativeBasicData get nativeBasicData =>
+      _backend.frontendStrategy.nativeBasicData;
+
   void addProgram(ir.Program node) {
     throw new UnsupportedError('KernelAstAdapter.addProgram');
   }